HIV-infected drug users may be at heightened risk for impaired glucose tolerance and type 2 diabetes mellitus in association with protease inhibitor (PI) therapy and co-infection with hepatitis C virus (HCV). To address these issues, the candidate proposes a five-year prospective study of 300 individuals with or at risk for HIV infection in order to examine the associations of HIV, PI therapy, and HCV infection with impaired glucose tolerance and type 2 diabetes. By nesting this study in two ongoing longitudinal studies of drug users in the Bronx, NY, the candidate will benefit from an extensive database and an established research infrastructure as well as the guidance of a group of experienced independent investigators. The specific aims of the project are: 1. To determine the prevalence of and factors associated with impaired glucose tolerance and type 2 diabetes in HIV-infected drug users, including PI therapy, HCV infection, sociodemographics, body mass index, and family history of diabetes. 2. To determine prospectively the impact of HIV infection, PI therapy, and HCV infection on the incidence of impaired glucose tolerance and type 2 diabetes. At semi-annual research visits, participants will undergo standardized interviews to assess sociodemographics, medical history, and drug use behavior, measurement of height, weight, and waist/hip ratio, and blood tests for CD4+ count, HIV viral load, HCV antibody, and HCV RNA level. In addition, fasting lipid profiles and body composition analysis using dual x-ray absorptiometry will be obtained. Oral glucose tolerance tests will be performed annually to screen for impaired glucose tolerance and diabetes. Active surveillance for clinical disease events will also be performed. The candidate's long term career goal is to become an independent investigator of HIV epidemiology in drug users. To achieve this goal, she will work closely with a multidisciplinary group of mentors with expertise in research related to HIV, diabetes, hepatitis C, and substance abuse. She will also complete coursework in the conduct of diabetes-related clinical research, addiction medicine, and the responsible conduct of research.